Arun Goyal

Extreme ultraviolet and x-ray transition wavelengths in Rb XXIV*

Energy levels, radiative rates, oscillator strengths and line strengths are reported for transitions among the lowest 97 levels of the(1s22s22p6) 3s23p2, 3s23p3 d, 3s3p3, 3p4, 3s3p23 d, and 3s23d2 configurations of Rb XXIV. A multiconfiguration Dirac–Fock(MCDF) method is adopted for the calculations. Radiative rates, oscillator strengths, and line strengths are provided for all electric dipole(E1), magnetic dipole(M1), electric quadrupole(E2), and magnetic quadrupole(M2)transitions from the ground level to all 97 levels, although calculations are performed for a much larger number of levels.To achieve the accuracy of the data, comparisons are provided with similar data obtained from the Flexible Atomic Code(FAC) and also with the available theoretical and experimental results. Our energy levels are found to be accurate to better than 1.2%. Wavelengths calculated are found to lie in EUV(extreme ultraviolet) and x-ray regions. Additionally, lifetimes for all 97 levels are obtained for the first time.

Extreme ultraviolet and soft x-ray spectral lines in Rb XXIX

An extensive theoretical set of atomic data for Rb XXIX in a wide range with L-shell electron excitations to the M-shell has been reported. We have computed energy levels for the lowest 113 fine structure levels of Rb XXIX. The fully relativistic multiconfigurational Dirac–Fock method (MCDF) within the framework of Dirac–Coulomb Hamiltonian taking quantum electrodynamics (QED) and Breit corrections into account has been adopted for calculations. Radiative data are reported for electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), and magnetic quadrupole (M2) transitions from the ground level, although calculations have been performed for a much larger number of levels. To assess the accuracy of results, we performed analogous calculations using flexible atomic code (FAC). Comparisons are made with existing available results and a good agreement has been achieved. Most of the wavelengths calculated lie in the soft x-ray (SXR) region. Lifetimes for all 113 levels have also been provided for the first time. Additionally, we have provided the spectra for allowed transitions from n = 2 to n = 3 within the x-ray region and also compared our SXR photon wavelengths with experimentally recognized wavelengths. We hope that our results will be beneficial in fusion plasma research and astrophysical applications.

Atomic structure calculations, partition function, and thermodynamic parameters for W LXXII and Au LXXVII

In this work, we present a theoretical study of W LXXII (Li-like W71+) and Au LXXVII (Li-like Au76+) by employing a multi-configuration Dirac Fock method approach within the framework of the Dirac-Coulomb Hamiltonian including quantum electrodynamics and Breit corrections. We have presented energies of the lowest 42 fine structure energy levels and radiative data for electric dipole (E1) transitions within the lowest 42 levels. We have made comparisons with available energy levels compiled by NIST and achieved good agreement. We have also discussed discrepancies between our results and other theoretical results with possible reasons of discrepancy. Due to inadequate data in the literature for higher excited states, analogous relativistic distorted wave calculations have also been performed using the flexible atomic code to assess the reliability and accuracy of our results. Furthermore, we have calculated the partition function and thermodynamic properties by the fine structure approach. The variation of the partition function, internal energy, and specific heat with temperature is also discussed. We believe that our presented work and future comparisons with experimental observations will be beneficial in fusion plasma.In this work, we present a theoretical study of W LXXII (Li-like W71+) and Au LXXVII (Li-like Au76+) by employing a multi-configuration Dirac Fock method approach within the framework of the Dirac-Coulomb Hamiltonian including quantum electrodynamics and Breit corrections. We have presented energies of the lowest 42 fine structure energy levels and radiative data for electric dipole (E1) transitions within the lowest 42 levels. We have made comparisons with available energy levels compiled by NIST and achieved good agreement. We have also discussed discrepancies between our results and other theoretical results with possible reasons of discrepancy. Due to inadequate data in the literature for higher excited states, analogous relativistic distorted wave calculations have also been performed using the flexible atomic code to assess the reliability and accuracy of our results. Furthermore, we have calculated the partition function and thermodynamic properties by the fine structure approach. The variation of ...